How can I hide source of spot lamp and keep the emission for the visible part
If you're using Cycles, you can disable shadows for the cylinder so the light can pass through it:

However, like this, the entire object won't cast any shadows which may be undesirable, so you could delete the face of the cylinder and add a new circle object in place of it which has its shadow disabled.
In EEVEE, you can disable shadows per material, so you can apply an emissive material for example to the face and have its shadow disabled:

Result with EEVEE:

Result with cycles: